ABOUT CANNED FOOD: WHENCE IT CAME:
THE HISTORY OF FOOD CANNING
The Natural Option: Contemporary Canning
The basic principles of canning have not changed dramatically since Nicholas Appert and Peter Durand developed the process. Heat sufficient to destroy microorganisms is applied to foods packed into sealed, or "airtight" containers. The canned foods are then heated under steam pressure at temperatures of 240-250°F (116-121°C). The amount of time needed for processing is different for each food, depending on the food's acidity, density and ability to transfer heat. For example, tomatoes require less time than green beans, while corn and pumpkin require far more time.
Processing conditions are chosen to be the minimum needed to ensure that foods are commercially sterile, but retain the greatest flavor and nutrition. All processes must be approved by the U.S. Food and Drug Administration. Once the cans are sealed and heat processed, the food maintains its high eating quality for more than two years and is safe to eat as long as the container is not damaged in any way. And, like the home canning process, no preservatives are added or necessary.
The sequence of steps in the canning process differs with the product. Fruits and vegetables may be peeled or pitted, and have stems removed prior to canning. Some vegetables receive a heat treatment before they are placed in the can to remove air and improve packing. (Think about the bulk of raw vs. cooked spinach!) Acid juices, like orange and tomato, and acid vegetables, such as sauerkraut, can be sterilized before they are placed into containers. Seafood is usually packed after being boned or shelled, with the exception of smaller fish like sardines and anchovies, or even salmon, which have bones that are softened by heating. Meats and fish, like tuna, are usually cooked to soften the flesh before canning, separated from bones, compacted and placed in cans with appropriate liquid.
"Information provided by the Canned Food Alliance. For hundreds of nutritious, delicious, easy recipes that use canned food, visit www.mealtime.org."